added day04

Cargo.lock

@@ -9,6 +9,7 @@ dependencies = [
  "day01",
  "day02",
  "day03",
+ "day04",
 ]
 
 [[package]]
@@ -22,3 +23,7 @@ version = "0.1.0"
 [[package]]
 name = "day03"
 version = "0.1.0"
+
+[[package]]
+name = "day04"
+version = "0.1.0"

Cargo.toml

@@ -9,4 +9,5 @@ opt-level = 2
 [dependencies]
 day01 = {path = "src/day01"}
 day02 = {path = "src/day02"}
-day03 = {path = "src/day03"}
+day03 = {path = "src/day03"}
+day04 = {path = "src/day04"}

src/day04/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day04"
+version = "0.1.0"

src/day04/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day04"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

src/day04/input04.txt

@@ -0,0 +1,140 @@
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+MASXMMMMMSMMMAMSSSSSSMMSMMSMSSMSSMASXMMMSMMASMMSMMMMAXXXXXAAMAMASXMASMXMSXSSSMXMXMAXXAMSXMXXMXMAMMMMMSAMASAMXAAAMAMAMAMAMXMMSASXMSXMAAXSSSSS
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+SAAMASMMMASXSXXASASMSMSSMAMAAXASMMMSMMSAMASASASXMAMXMAAAXAXXXSSMSMSASXAMASMSSXMAMMAMXXMMMMXXMASAMMMMMSMMMASAAMMMMMXAMXMAXAXMAXAAAXXAXMSMSSMS
+XMXXAAAAMXMAXAMASASAMXMAMMSSMSMSAAMAMASASAMXSMMMMMMXMMMMSMMMMMAAAASXXMAXXMAXMASAMXMMMMXAMXAASAMXMMXAAMMSSXMXSMXASMMXMAMMSMMAMSMMSSMXMAAAXAAX
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+SAAAXMASXMASAXMXMMAMMASMMMASXMAMAMSXMAMXMMMMXMASMMSASAMSXSSSXSMMXSAASAAXMAMMXSAXASMXMSMAMMMASASMXSSMMMAMXAMXMASAXAMAAAMXXXMSSSSMMASASASXMXMA
+AXMMMMMMASMMAXAMXAAAMXMSAMMSAMXSAMSXMXSSMSAAXSASAAMMMMMMAMMMAXAXAXXMMMMSXMMSAMXMXMSAAAXAMAMXMAMXASXSASAMSMMXMASMSMMMSMSSMAMAAMAAMAMAMASXMAMS
+MSMASAXMAMXMMMSSMSXXMXAMXMSSMMMMXSMASAMAASMXMMASMMMSAMASASXSMSSMASXMMAAAASXMASXXAXSXSASXSXSXMSMMMMAAMSAMAXXAMXMXAXXMAXAAMSMMSSSMMSMMMSMMSASA
+XAMASMSMASAAAAAMAMMSSMMMSMMMAMAAXXMAMXSMMMAMSMMMXMASASASMSAAXAAMAMXASMMXMMAMMXAMSXMAMMAMXMSXMAMAAMXMXSXMSMMASAXSSSSSSMSSMAAXXAXXAMASXAAASXSM
+AMMXSASMAMMXMMSSXSAAAAXAAAASASMSMMMMSMMXMMXMAAMAMMASAMMSAMXMMSSMASMMMMSMMSSMXMXMMAMXMAMAAAXAXAXSSSXMAXSMAASMMMMAAAAAXXAAXSXMMAMMMSAMXMMMSASX
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+SAMXSMMSMAXAMXSMSMMAMAMAMXMMMMXMSSXSASXAXMMMSXSASMMSAMMSMMMASMASMSAXMSSMMSSMMMAXASAMAXMXMXAXMXAMMMMSAMXAXAMMAMXAXMXAXAAMMSAMXSXXAMMSMXXXMXMS
+MASAXMAAMXSXSAXAMAXMSAMXMASAXAXMAXASAMMSMAMAAXMMMMAMXXXAAASAMXAXASXMSAMXMAXAASASASASAMSAMXSMXMASXXAMASXMMSAMXSXMXSSMXSXMXMASMMMSMMAAMMSSMASA
+MXMMXMSSSXAXMMXXSXMASASMMAMXMMSMASMMMMAASAMMSSSMSMSXMMSXSMSAXXAMXMSXMASASAMXMSASASAMAXSASAMAAXMXMXMSMMAAAAASAMXSAMMSAMAMXSAMXAAAAMSXSAAAAXXM
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+XXAMMSMMSMSMMXMMAAAXMASXMMAMMSSXMMSXAMXMAMMAMXAXXAMMAASXMSMSMMSMSXSASAMXAAMAMSSMASXSMASASXSXMXAAXMAXMAMAMXXXSASMMMMMMMSSSSSMAXMSAMSMSAAXAMXA
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+MAAMMXSAMSSXSASXSXSSXAMASXMSMSSSMASAXXSMAMSMMMSAAXAASMSSMMSXMASAMAMAMAXAAAAMMMSMAXXAXXMAMASAMAXXMAXAMAXMMXSAMSMXMXASMMSXMAXSAMXASMSSMXMAMAAM
+MMXMXSSXMAMXMASMSAAXXMMASXMAAMAAMMMMMAXMSXMASAMXSMMSSXAXSXAXMXMAMXXXSSMSMSMSAMXMSXMMSMMXSAMMSSXMSMSSMSMXXAAASMMXMXAXXXXXMXXMASMMSAAAAXSXSSSM
+MSASXAMXMASXSXSAMMMMSXMASASMSMSMMSAMMSMAMMMAMASMXMMMMMMMMMMMMSSXMMMXMAMXMAXMASMAXXASAMAMMMMMAMXAAAAMAMXSMSSMMXXAXMMSMXMMSAXSAMAMMMMMSMMAAAXX
+ASASMXMASMMASAMAMXXASAMASMMAAAAAMMAMAAMXMAMXSAMAAXMAAAAAAAXAAASAAAXASAMAMAXXAAMAMSSXMAXSAAMMASMSMMMMXMAXMXAAXSSMSAASMSXAAAXMASMMAAAAAAMSMMMA
+XMXMASMXSXMSMXSSMAMXSXMXSXMSMSMSXSSMSXSASXSAMXXSASXSSSSSSSSMSSSSMMSASMSXSMXMASMAMSASXAXSMSSSSMMAXSMXSMXSMSSMMAXASMXMASMXMSMSAMMSXSMSSSMXXXSX

src/day04/src/lib.rs

@@ -0,0 +1,2 @@
+pub mod part04a;
+pub mod part04b;

src/day04/src/part04a.rs

@@ -0,0 +1,52 @@
+use std::fs::File;
+use std::io::Read;
+
+pub fn day04a() -> u64 {
+    // read file (that for sure exists) into two lists
+    let mut file: File = File::open("src/day04/input04.txt").unwrap();
+    let mut file_content: String = String::new();
+    file.read_to_string(&mut file_content).expect("Can't read file");
+
+    // create n*n matrix from input
+    let mut matrix: [[char; 140]; 140] = [[' '; 140]; 140];
+    file_content.split("\n").enumerate().for_each(|(line_nr, line)| {
+         line.chars().enumerate().for_each(|(col_nr, ch)| {
+             matrix[line_nr][col_nr] = ch;
+         });
+    });
+
+    // examine every element in matrix
+    let mut count: u64 = 0;
+    for row in 0..140isize {
+        for col in 0..140isize {
+            // skip if it's not X
+            if !matrix[row as usize][col as usize].eq(&'X') { continue }
+            // if enough space search in X+
+            if col + 3 < 140 { count += search_xmas(&matrix, row, col, 0,1) }
+            // if enough space search in X-
+            if col > 2 { count += search_xmas(&matrix, row, col, 0, -1) }
+            // if enough space search in Y+
+            if row + 3 < 140 { count += search_xmas(&matrix, row, col, 1, 0) }
+            // if enough space search in Y-
+            if row > 2 { count += search_xmas(&matrix, row, col, -1, 0) }
+            // if enough space search in X+Y+
+            if col + 3 < 140 && row + 3 < 140 { count += search_xmas(&matrix, row, col, 1, 1) }
+            // if enough space search in X+Y-
+            if col + 3 < 140 && row > 2 { count += search_xmas(&matrix, row, col, -1, 1) }
+            // if enough space search in X-Y+
+            if col > 2 && row + 3 < 140 { count += search_xmas(&matrix, row, col, 1, -1) }
+            // if enough space search in X-Y-
+            if col > 2 && row > 2 { count += search_xmas(&matrix, row, col, -1, -1) }
+
+        }
+    }
+
+    count
+}
+
+fn search_xmas(matrix: &[[char; 140]; 140], row: isize, col: isize, x: isize, y: isize) -> u64 {
+    if !matrix[(row+  x) as usize][(col  +y) as usize].eq(&'M') { return 0 }
+    if !matrix[(row+2*x) as usize][(col+2*y) as usize].eq(&'A') { return 0 }
+    if !matrix[(row+3*x) as usize][(col+3*y) as usize].eq(&'S') { return 0 }
+    1
+}

src/day04/src/part04b.rs

@@ -0,0 +1,60 @@
+use std::fs::File;
+use std::io::Read;
+
+pub fn day04b() -> u64 {
+    // read file (that for sure exists) into two lists
+    let mut file: File = File::open("src/day04/input04.txt").unwrap();
+    let mut file_content: String = String::new();
+    file.read_to_string(&mut file_content).expect("Can't read file");
+
+    // create n*n matrix from input
+    let mut matrix: [[char; 140]; 140] = [[' '; 140]; 140];
+    file_content.split("\n").enumerate().for_each(|(line_nr, line)| {
+        line.chars().enumerate().for_each(|(col_nr, ch)| {
+            matrix[line_nr][col_nr] = ch;
+        });
+    });
+
+    // examine every element in matrix
+    let mut count: u64 = 0;
+    for row in 1..139 {
+        for col in 1..139 {
+            // skip if it's not A
+            if !matrix[row][col].eq(&'A') { continue }
+            // if enough space search in X+
+            count += is_x_mas(&matrix, row, col);
+        }
+    }
+
+    count
+}
+
+fn is_x_mas(matrix: &[[char; 140]; 140], row: usize, col: usize) -> u64 {
+    if !validate_tl_br(matrix, row, col) { return 0 }
+    if !validate_tr_bl(matrix, row, col) { return 0 }
+    1
+}
+
+fn validate_tl_br(matrix: &[[char; 140]; 140], row: usize, col: usize) -> bool {
+    match matrix[row-1][col-1] {
+        ch if ch.eq(&'M') => {
+            matrix[row+1][col+1].eq(&'S')
+        }
+        ch if ch.eq(&'S') => {
+            matrix[row+1][col+1].eq(&'M')
+        }
+        _ => false
+    }
+}
+
+fn validate_tr_bl(matrix: &[[char; 140]; 140], row: usize, col: usize) -> bool {
+    match matrix[row-1][col+1] {
+        ch if ch.eq(&'M') => {
+            matrix[row+1][col-1].eq(&'S')
+        }
+        ch if ch.eq(&'S') => {
+            matrix[row+1][col-1].eq(&'M')
+        }
+        _ => false
+    }
+}

src/day04/story04a.txt

@@ -0,0 +1,39 @@
+"Looks like the Chief's not here. Next!" One of The Historians pulls out a device and pushes the only button on it. After a brief flash, you recognize the interior of the Ceres monitoring station!
+
+As the search for the Chief continues, a small Elf who lives on the station tugs on your shirt; she'd like to know if you could help her with her word search (your puzzle input). She only has to find one word: XMAS.
+
+This word search allows words to be horizontal, vertical, diagonal, written backwards, or even overlapping other words. It's a little unusual, though, as you don't merely need to find one instance of XMAS - you need to find all of them. Here are a few ways XMAS might appear, where irrelevant characters have been replaced with .:
+
+..X...
+.SAMX.
+.A..A.
+XMAS.S
+.X....
+
+The actual word search will be full of letters instead. For example:
+
+MMMSXXMASM
+MSAMXMSMSA
+AMXSXMAAMM
+MSAMASMSMX
+XMASAMXAMM
+XXAMMXXAMA
+SMSMSASXSS
+SAXAMASAAA
+MAMMMXMMMM
+MXMXAXMASX
+
+In this word search, XMAS occurs a total of 18 times; here's the same word search again, but where letters not involved in any XMAS have been replaced with .:
+
+....XXMAS.
+.SAMXMS...
+...S..A...
+..A.A.MS.X
+XMASAMX.MM
+X.....XA.A
+S.S.S.S.SS
+.A.A.A.A.A
+..M.M.M.MM
+.X.X.XMASX
+
+Take a look at the little Elf's word search. How many times does XMAS appear?

src/day04/story04b.txt

@@ -0,0 +1,26 @@
+The Elf looks quizzically at you. Did you misunderstand the assignment?
+
+Looking for the instructions, you flip over the word search to find that this isn't actually an XMAS puzzle; it's an X-MAS puzzle in which you're supposed to find two MAS in the shape of an X. One way to achieve that is like this:
+
+M.S
+.A.
+M.S
+
+Irrelevant characters have again been replaced with . in the above diagram. Within the X, each MAS can be written forwards or backwards.
+
+Here's the same example from before, but this time all of the X-MASes have been kept instead:
+
+.M.S......
+..A..MSMS.
+.M.S.MAA..
+..A.ASMSM.
+.M.S.M....
+..........
+S.S.S.S.S.
+.A.A.A.A..
+M.M.M.M.M.
+..........
+
+In this example, an X-MAS appears 9 times.
+
+Flip the word search from the instructions back over to the word search side and try again. How many times does an X-MAS appear?

src/main.rs

@@ -5,6 +5,8 @@ use day02::part02a::day02a;
 use day02::part02b::day02b;
 use day03::part03a::day03a;
 use day03::part03b::day03b;
+use day04::part04a::day04a;
+use day04::part04b::day04b;
 
 fn main() {
     let exercises: Vec<(&str, fn () -> u64)> = vec![
@@ -14,6 +16,8 @@ fn main() {
         ("day02:B", day02b),
         ("day03:A", day03a),
         ("day03:B", day03b),
+        ("day04:A", day04a),
+        ("day04:B", day04b),
     ];
 
     let start: Instant = Instant::now();